1. Field of the Invention
The present invention relates to a pressure-sensitive adhesive sheet, in particular to a pressure-sensitive adhesive sheet for use in radiography. More particularly, the present invention relates to a pressure-sensitive adhesive sheet that allows incorporation of particular information on a subject into radiograph or reproducing a scale or grid pattern in a radiograph that has taken a picture of the inside of the body of a subject so that the size of the inside of the body or the position of the organs of the subject can be determined with ease in a simple manner.
2. Description of the Related Art
Hitherto, to aid medicine, a ruler is used in order to determine the position of puncture when injection is to be performed or the position of the site where operation is to be practiced. In particular, when organs inside the body of a subject is targeted, the determination of position of puncture or of the site where operation is to be practiced by applying a ruler onto the radiograph. More particularly, after radiography, a ruler is applied to the obtained radiograph. The distance between the marked place to the target place is measured on the skin of the patient, and then the position of puncture or operation site is marked with an oil-base ink, for example, so that the position of puncture or operation site can be determined.
The determination of position with a ruler has the problems that bringing and using rulers is troublesome and that accurate measurement is difficult for bent portions. Further, generally the radiograph and the object radiographed are not in an equi-powered relationship (i.e., not at the same magnification or reduction ratio) to each other, i.e., either high-powered (magnified) or low-powered (reduced), so that accurate measurement of the positions is difficult if a ruler is used on the obtained radiograph.
Also, image processing of a radiograph image on a computer has been performed in order to make an accurate measurement of the size of organs, etc. However, introduction of image processing apparatus incurs much cost so that the introduction of such an apparatus is not realistic for surgery or small-sized hospitals.
On the other hand, JP-A-8-56983 (1996) discloses a medical pressure-sensitive adhesive tape whose tape is provided with a scale. Use of the pressure-sensitive adhesive sheet obviates the trouble of its bringing or use and facilitates measurements of bent portions.
However, use of such a medical pressure-sensitive adhesive tape is contemplated upon observation of the state of disease using a camera or video camera. Hence, like the use of a ruler, it is difficult with such a tape to determine the position of an organ or the like in the body of a subject with accuracy.
In view of the above, an object of the present invention is to provide a pressure-sensitive adhesive sheet for radiography that allows easy and accurate determination of information on the position of puncture or operation site in the inside of the body of a subject or information on the subject from a radiograph obtained using it.
The present inventors have made intensive research with view to achieving the above object and as a result they have found that use of a pressure-sensitive adhesive sheet including a plastic sheet having formed on at least one surface thereof a print layer containing an X-ray absorbing metal and a pressure-sensitive adhesive layer on either one of the surfaces of the resulting plastic sheet in radiography enables one to determine the position of puncture or operation site in the inside of the body of the subject easily and accurately. The present invention has been achieved based on this discovery.
Accordingly, a pressure-sensitive adhesive sheet comprising a plastic sheet having on one surface thereof a pressure-sensitive adhesive layer, wherein the plastic sheet has on at least one surface thereof a print layer having a thickness of 40 to 1,000 xcexcm and containing 30 to 90% by weight based on the total weight of the print layer of an X-ray absorbing metal.
Here, the pressure-sensitive adhesive layer may be provided on the print layer.
The pressure-sensitive adhesive layer may be provided on a surface of the plastic sheet opposite to a side where the print layer is provided and wherein a light-transmitting layer is provided on the print layer.
Preferably, the X-ray absorbing metal has a density of 8,000 kg/m3.
The X-ray absorbing metal is preferably tungsten.
The print layer may be in the form of a scale pattern or grid pattern.
The scale pattern may be a numerical value scale for the measurement of lengths.
The pressure-sensitive adhesive sheet may have an arcuate end in its longitudinal direction.
The pressure-sensitive adhesive sheet may further comprise a release liner on a surface of which the pressure-sensitive adhesive sheet is applied.
The release liner may be provided with a slit for division.
In the present invention, a print layer is provided on one surface of a plastic sheet. The print layer contains an X-ray absorbing metal such as tungsten in an amount of 30 to 90% by weight based on the total weight thereof and has a thickness of 40 to 1,000 xcexcm. The print layer may be provided in the form of a scale or grid line or the like pattern and in this case, radiography using the pressure-sensitive adhesive sheet of the present invention can reproduce the printed pattern in the obtained radiograph sharply. This offers advantages that the size of the inside of the body of a subject or accurate position of a target organ can be grasped easily so that appropriate medical treatments can be offered.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments.